Method of making guns and other hollow metal articles



Sept. 15, 1925. 1,553,825

F. LANGE NBERG METHOD OF MAKING GUNS AND OTHER HOLLOW METAL AR Filed March 28, 1925 TICLES CASTING H FELL MACHNED 3 5 5 W E: 5 2 W7/ 7 [E I EU I Srzcouo ANNEALlNG F\R5T EXPANEHNG f 5 5 T|Q 4 i- 51 X f J1 FlNmsHD SECOND EXPANDING INIVELNLEIVZ Patented Sept. 15, 1925.

UNITED STATES PATENT OFFICE.

FREDERICK C. LANGENBERG, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR OF ONE- HALF TO TRACY C. DICKSON, F WATERTOWN, MASSACHUSETTS.

METHOD OF MAKING GUNS AND OTHER HOLLOW METAL ARTICLES.

Application filed March 2 8, 1925. Serial No. 19,172.

To allwhpmit may concern:

Be it known that I, FREDERICK C. LAN- GENBERG, a citizen of the United States, residing at Cambridge, county of Middlesex, 6 State of Massachusetts, have invented a certain newand useful Improvement in Methods of Making Guns and Other Hollow Metal Articles, of which the following is a specification, reference being had therein to 10 the accompanying drawings.

The present invention relates to the manufacture of guns and other hollow metal articles particularly of steel. Heretofore, it has been known that if an article ofsteel is expended or stretched beyond its elastic limit, the elastic limit will be permanently raised. Attempts have been made to -apply this principle to the manufacture of guns, but no considerable commercial success has been attained chiefly because it has not been possible to regulate and distribute the amount of expansion over an article of irregular thickness. In an application filed March 28,1925, Serial No. 19,001, I have disclosed 5 anap ariitus and method which overcomes this dlfiiculty. I have also discovered that. by the use of the apparatusand method therein described which consists essentially in regulating the amount of expansion permitted to the article by placing it within a strong container the interior of which is complementanyfin size and shape to the final shape to be given the article, due allowance being made for contraction, it is possible to improve and simplify further the manufacture of guns, shells and otherhollow steel articles. In this connection I also take advantage of the method described in a companion application filed March 28, 1925, Serial No. 19,173, which consists essentially of performing the expansion of'the article in two or more stages and annealing the article between the successive expanding steps. Generally speaking, the present invention is based on the discovery that the hollow article can be made directly from a casting without the intervention of any forging. or heat-treating steps, thereby greatly simplifying the process of making such articles as guns and shells, reducing the time and plant expenditure necessary for their manufacture and thus materially reducing the expense and increasing the possible production of such articles in time of war.

. and experiment.

The invention will be fully understood from the following description when taken in connection with the accompanying drawings and the novel features thereof will be pointed out and clearly defined in the claims at the close of this specification.

In said drawings:

Fig. 1 shows the original casting.

Fig. 2 illustrates the first annealing step.

Fig. 3 shows the article after it has been machined.

Fig. 4 shows the first expanding step. Fig. v 5 illustrates the second annealing step.

Fig. 6 shows the second expanding.

Fig. 7 shows the finished article.

In practising my invention, I first cast the article to a shape determined by calculation In Fig. 1, at A, I have shown the casting for the article. The article is then placed in a furnace B, Fig. 2, and annealed. After being annealed, the article is machined on whatever surface requires it. This is indicated at C in Fig. 3. The machined article A is then placed in a suitable container D (Fig. 4) the interior of which is larger than the article by an amount which willstop the expansion of the article at a predetermined point determined 'by the desired increase in the elastic limit. .Thereafter, it is subjected to an internal expanding pressure, preferably as described in my application filed March 28, 1925, Serial No. 19001. Thereafter, it is removed from the container and again annealed, this being indicated in Fig. 5. After cooling,

' the article A" is placed in another container E (Fig. 6) the interior of which is larger than the article by the second increase in the elastic limit desired. The article is then expanded and removed from the container. Thereafter as shown in Fig. 7 if the article is a gun, it is rifled, or if it is a shell or other article, subjected to any finishing operations which may be required.

I find that articles such as guns, can be manufactured by this process with 'all the accuracy desired and can be made from a single casting instead of being built up from tubes, hoops or rings and that the distribution of metal lengthwise of the gun can be substantially improved while at the same time producing a gun which is materially stronger than built-up guns. By thus doing away with the numerous machining, shrinking, forging and heat treating processes involved in the Vmanufacture of built-up guns the expense is very greatly reduced. Likewise, in the manufacture of shells, the expense is materially lessened.

It will be understood of course that in certain cases it is possible to do the expansion in a single stepwithout resorting to intermediate annealing, but in many cases the best results will be obtained by doing the expansion in two or more successive steps between which the gun is annealed.

While I have described the present invention as applied to the manufacture of guns, it will be understood that it is also applicable to the manufacture of other articles, such as shells, gas containers, tubes and the like.

What I claim is:

1. The method of making a gun or other hollow steel article which includes casting the metal, annealing the' casting, and subjecting it to an internal expanding pressure while enclosed in a container the shape of which is complementary in shape to the final shape ofthe article to be produced.

2. The method of making a gun or other hollow steel article which comprises casting the metal, annealing the casting, machining it and subjecting it to an internal expanding pressure while enclosed in a container the interior of which is complementary in shape to the final shape of the article to be produced.

3. The method of making a gun or other hollow steel article which comprises casting the metal, machining it and subjecting it to an internal expanding pressure in successive stages and annealing the articles between the'stages, the article during each expanding step being enclosed within a container the interior of which is complementary in form to the form which the article is to have after being expanded.

In testimony whereof I afiix my signature.

- FREDERICK o. LANGENBERG. 

